The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical automatic transmission includes a hydraulic control system that is employed to provide cooling and lubrication to components within the transmission and to actuate a plurality of torque transmitting devices. These torque transmitting devices may be, for example, friction clutches and brakes arranged with gear sets or in a torque converter. The hydraulic control system includes a torque converter clutch control valve system that changes the flow of hydraulic fluid inside the torque converter equipped with a lockup clutch. The torque converter can then be employed in a “lockup clutch—open” state and a “lockup clutch—closed” state. In the open state, the torque converter control valve is intended to provide sufficient flow of hydraulic fluid through the torque converter to cool it. When the torque converter control valve is in the closed state, the torque converter control valve reverses and reduces the flow of hydraulic fluid through the torque converter as compared to the open state. If, however, the torque converter control valve fails in between the open and closed states or sticks in the closed state without limiting the lockup clutch speeds inside the torque converter, heat is generated inside the torque converter without sufficient flow of hydraulic fluid to cool the torque converter, which leads to hazardous high temperature conditions.
Accordingly, there is a need for a torque converter clutch control valve system that provides detection of the torque converter control valve in a faulted state.